HEAB

255

Fig. 119.—Effusion of blood upon the
surface of brain.

patient suffers from serious after-effects due to permanent damage to the
brain tissue.

Compression of the Brain.—This is a clinical condition caused by
increased intracranial pressure which disturbs the functions of the brain.
It may result from a depressed fracture of a skull bone or a foreign body,
intracranial haemorrhage, acute spreading oedema, inflammatory exudation
and presence of tumours, gummata or abscesses.

Symptoms.—These may come on immediately, or may be delayed for
some hours or days, after receiving the injury. The symptoms are those of

coma. There is complete loss of
consciousness. The patient can-
not be roused by shouting or
even by shaking. The face is
flushed, and the pupils are dilated
and insensible to light, but they
may be contracted or unequal, if
there is a small degree of com-
pression over a limited area of the
brain. The temperature of the
body is normal or sub-normal, but
may be above normal. The pulse
is full and slow, but becomes
rapid and irregular towards death.
Breathing is slow, laboured and
stertorous with the lips and
cheeks being puffed in and out.
There is paralysis of the muscles and extremities according to the area of
the brain involved. The reflexes are lost, and retention of urine occurs
from paralysis of the bladder. Faeces pass involuntarily owing to relaxation
of the sphincter ani, although marked constipation is usually present.
Sometimes convulsions precede death.

In some cases partial recovery may occur owing to the arrest of blood
in an injured artery of the brain by the formation of a clot, but death may
take place later when the clot is disturbed and fresh haemorrhage takes
place owing to the heart being excited by exercise or indulgence in alcohol.

Permanent recovery may occur when the compressing factor, such as a
depressed piece of a fractured cranial bone, is removed by trephining. In
such cases, however, remote effects, e.g. headache, loss of memory, epilepsy,
paralysis, or insanity, may supervene from permanent damage to the brain
tissue.

Intracranial Haemorrhage.—Haemorrhage within the cranium may be
(a) extradural, (b) subdural, (c) subarachnoid and (d) intracerebral.

(a) Extradural Haemorrhage.—This occurs between the skull and the
dura mater, and is caused by rupture of the middle meningeal artery,
diploic veins or dural venous sinuses. It is generally associated with
fracture of the skull, and a portion of the dura mater is often torn off the
bone, when a large extradural effusion of blood collects, burrowing down-
wards into the base of the skull, and presses upon the side of the brain.
Extradural haemorrhage is occasionally found without any fracture or any
external injury on the side of the head where a blow is struck or on its
opposite side. In such circumstances it forms a localized clot, which com-
presses and flattens the brain.

(b) Subdural Haemorrhage.—This occurs into the subdural spaoa be-
tween the dura mater and the arachnoid as a result of rupture of &er A^I
venous sinus, or a cortical vein if the arachnoid has been torn or laceration